Alton Towers personnel operated the Smiler rollercoaster in wind speeds exceeding manufacturer’s instructions the day the ride crashed last year.
16 people were injured – five seriously – when a fully-laden train collided with a stationary empty vehicle on 2 June.
Park operators Merlin Entertainments are appearing at Stafford Crown Court for a two-day sentencing hearing, after pleading guilty to failings under the Health and Safety At Work Act in April this year.
The courtroom heard that the ride was being operated in wind speeds of 45mph – above the 34mph limit set by the rollercoaster’s German manufacturers Gerstlauer.
Sensors that should have detected sustained wind speeds above 34mph failed to activate.
Alton Towers said it had subsequently implemented improved safety procedures to prevent the ride from being operated in high winds, which the prosecution alleged were responsible for causing the empty train to stall.
The four riders on the front row of the laden train suffered severe injuries, with two requiring leg amputations.
’90mph car crash’
The five most seriously injured victims – including a woman who suffered severe internal injuries – were all in court for the hearing.
Health and Safety Executive (HSE) prosecutor Bernard Thorogood described how the force of the two trains colliding was the equivalent to a 1.5-tonne family car crashing at 90mph.
The court heard how engineers overrode the ride’s safety systems, as they did not spot the empty stationary car following a visual check of the track due to “blind spots” existing.
However, released footage from the ride’s CCTV system’s clearly showed the empty train in both its stationary position and its preceding backwards and forwards motion after failing to complete a track inversion.
The rescue operation took more than four-and-a-half hours due to access restrictions
The courtroom was told that the engineers on the day were not aware of the content of the ride’s operating instructions.
Mr Thorogood added that although there had been “a number of human errors”, the fault was “with the employers”.
He said engineers, responding to a fault, were “without guidance from above”.
“The fault is with the defendant for not devising a scheme for not guiding the work of the engineers,” he added.
The Smiler reopened in March this year, after remaining closed for the rest of the 2015 season following the June crash.
With company turnover now a key factor in the determination of fines in sentencing guidelines, Merlin is likely to be given a multi-million pound fine when the hearing concludes on Tuesday.
Judge Michael Chambers QC asked for the company’s turnover, which was put at £300 million in a 12-month period ending in August this year.
The court was also told that Merlin chief executive Nick Varney had a salary and bonus package of £733,000 in 2015.
Varney was in court alongside Alton Towers divisional director Ian Crabbe.
Merlin said that there had been no resignations as a result of the accident.
The concluding day of the hearing will begin at 10:30 tomorrow.